On Wed, Oct 22, 2014 at 10:46:39PM +0100, Richard W.M. Jones wrote: > Initially I thought this was a qemu bug, so I was tracking it here. > > https://bugs.launchpad.net/qemu/+bug/1383857 > > In brief, virtio devices don't show up in the guest when using kernel > 3.18.0+rc1. I'm also using 64k pages, but I don't know if that is > related. > > I did a bisect and it pointed at: > > 421520ba98290a73b35b7644e877a48f18e06004 is the first bad commit > commit 421520ba98290a73b35b7644e877a48f18e06004 > Author: Yalin Wang <Yalin.Wang@xxxxxxxxxxxxxx> > Date: Fri Sep 26 03:07:09 2014 +0100 > > ARM: 8167/1: extend the reserved memory for initrd to be page aligned > So I'm still seeing this bug. I have found out that if I remove -initrd from the qemu command line then the kernel is able to boot. Obviously in order to do that I had to compile the virtio drivers into the kernel, but I also tried the same kernel with -initrd and that failed, so the act of compiling the virtio drivers into the kernel isn't what fixed it. It's using the -initrd option at all which is what is failing. My initrd is not especially large (1.5 MB). I tried using dummy initrd files of various sizes to see if there is a limit to the size of the initrd: size of -initrd file of zeroes result 0 bytes guest boots OK 64 Kbytes (1 page) guest boots OK 256 Kbytes guest boots OK 1 Mbyte guest boots OK 2 Mbytes guest boots OK But these are all full of zero bytes, so the kernel essentially ignores them - ie. it won't allocate further memory. I tried an initrd which was a real cpio file, but basically empty (it contained 1 block of data), and virtio devices DON'T show up. size of -initrd cpio file result 512 bytes no virtio devices show up So something to do with how or where the initrd gets unpacked? Is there somewhere that we document the memory map for ARM virtual machines? Rich. -- Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones Read my programming and virtualization blog: http://rwmj.wordpress.com virt-df lists disk usage of guests without needing to install any software inside the virtual machine. Supports Linux and Windows. http://people.redhat.com/~rjones/virt-df/ _______________________________________________ kvmarm mailing list kvmarm@xxxxxxxxxxxxxxxxxxxxx https://lists.cs.columbia.edu/mailman/listinfo/kvmarm
